What is normal?

Abigail
I have been bleeding for 2 weeks now. It started with spotting, then dark brown for a week, then it's been bright red/pink for 3 days now. At first the bright red/pink was heavy, gushing at times. Some clots. Now it fills up a pad within 2-4 hrs. Experiencing some cramping. 
Usually my periods are light/medium. Hardly notice it at all. I've never had it go from dark brown to bright red before. Help?! Should I call my dr?  Anyone experience this before.